Sulfamethoxazole and Trimethoprim


A combination drug used to treat urinary tract infections, respiratory infections, skin infections, ear infections, and prostatitis.

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Sulfamethoxazole and Trimethoprim Basics

Sulfamethoxazole and Trimethoprim, or TMS, is a combination of two antibiotics that work together to fight different types of bacteria. TMS treats a wide variety of infections, including urinary tract infections, skin infections, enteritis, pneumonia, otitis media, prostatitis, coccidiosis, and kennel cough. It also treats E. coli, Klebsiella, Enterobacter species, Bordatella bronchiseptica, Staphylococcal, and Shigella. TMS  inhibits the production of nucleic acids and proteins. This action prevents the bacteria’s DNA from replicating, causing it to die.

Sulfamethoxazole and Trimethoprim requires a prescription from your veterinarian. It is available in a 480mg and 960mg tablet. It is also available in an oral suspension (200mg/40mg/5mL).

Sulfamethoxazole and Trimethoprim Directions

Use as directed by your veterinarian, and follow all instructions printed on the prescription label. Complete the entire prescription unless instructed otherwise by your veterinarian. Dosage and duration of treatment depend on the condition being treated and response to the medication. Allow your pet access to plenty of water throughout treatment. Give doses with food if stomach upset occurs.

Store at room temperature, protected from light and moisture.

Sulfamethoxazole and Trimethoprim Warnings

Keep out of the reach of children and pets. Do not use in animals with a known hypersensitivity to sulfa drugs or in animals that are pregnant or nursing. Do not use this medication in animals suffering from liver or kidney disease. Keep animals that are taking TMS out of direct sunlight, as it can increase sensitivity to the sun. If you notice any behavioral or physiological changes in your pet while administering Sulfamethoxazole and Trimethoprim, contact your veterinarian immediately.

Adverse Reactions and Serious Side Effects

Adverse reactions and serious side effects are rare, however, they can occur. In the case of a more serious reaction, seek veterinary attention. Common signs of an allergic reaction or serious side effect are hives, breathing difficulty, facial swelling, unusual bleeding or bruising, or jaundice.

If you have any additional questions regarding this product, please contact us at (877)220-6337. A member of our pharmacy staff will be happy to assist you!

Additional information


Oral Suspension, Tablet

Prescription Strength

200mg / 40mg / 5mL, 480mg, 960mg